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Have you ever wondered what sort of things go through the mind of a naturalist? No doubt it varies from person to person, as all such things do, so I can only tell you for sure the things that often have me entranced as I try to puzzle them out. Here is a "for instance."

A couple days ago, while leading a school program, one of our volunteers found this fluffy white mass on the back of a dried leaf that had fallen from one of the trees along our path. Now, I knew it was an egg or pupa case, and I knew I had seen it before, but I could not recall what species it belonged to or any details of its life history.

When we got back to the visitor center, and while the students took their lunch break, I grabbed my copy of "Tracks and Signs of Insects" by Eiseman and Charney, and searched for the answer I was sure was in there. No luck.

And yet I KNOW I had seen (and identified) it before.

My go-to site for all insect ID is the terrific website BugGuide.Net. If you haven't been there yet, you must do so soon. These folks are terrific: you send them a photo of some mystery insect or insect part, and often within a couple hours you have an answer as to what it is.

So, off I sent my photo, and sure enough, the answer soon came back: Braconid Wasp, subfamily Microgastrinae.

My work had only just begun.

This morning I have been scouring my insect books and the Web in search of details about this small ball of fluff. Eggs? Pupae? Life cycle? And while some information is quite readily available, much (to me) still remains a mystery.

For example:

There are about 2000 described species in the subfamily Microgastrinae. Scientists suspect there are 5-10,000 species possible; that is a lot of unknowns.

The Microgastrinae are a subfamily of the Brachonid wasps, which are the second largest family of wasps in the world (right after the Ichneumonids, just in case you were wondering). Over 17,000 species of Brachonids are recognized today, but again, it is believed there are thousands more that we know little to nothing about.

Brachonids are parasitic wasps. In general, they lay their eggs on the host (in the case of the Microgastrinae, the hosts are the caterpillars of moths and butterflies), the eggs hatch, consume the host, pupate, and then the adults fly off to continue the cycle.

If you have ever seen a tomato hornworm in your garden that is covered with small white ovals all over its back, you are seeing the pupal cases of a Microgastrinae. The larvae ate the caterpillar's "blood" (hemolymph) and internal organs, then tunneled out of its dying body to spin silky cocoons on this back. This is a good thing for you and your tomatoes - not so good for the caterpillar.

Anyway, this was all familiar territory for me -- I have seen many a hornworm covered with cocoons, and plenty more photos of other species of caterpillars similarly parasitized. But the fluffy mass that is currently sitting on my desk has no (apparent) caterpillar host associated with it. Why?

I continue to search the Web, but even BugGuide has let me down - there are photos a-plenty, but mostly all it says about them is "Brochonid Wasp - Microgastrinae" - no life histories.

The best I can come up with at this time is that this is a collection of Microgastrinae pupae (and if I teased apart the mass I would surely find all the little oval pupal cases), and perhaps the desiccated husk of the host caterpillar has fallen away, since by now its purpose is fulfilled and it is obsolete.

Knowing me, however, I shall continue to puzzle about this until one day I have found THE answer.

One of my favorite activities to do with a group of kids is just let them go for an explore, with me there to answer their questions and guide their discoveries.

We recently had a group of second and fifth graders out for a Discover Nature Hike, and we couldn't have had a more perfect autumn day for it! The sun was out, the sky was blue, the leaves were changing color and drifting to the ground. It was just warm enough that the possibility of seeing snakes basking on the pavement, or turtles on logs at the pond, was real.

The students I had in my group were second graders, and they were full of curiosity and in full explorer mode. We first headed out to an old stone wall that runs along part of the driveway. Armed with hand lenses, they checked out seeds, mosses, lichens, tree bark. One girl turned to me to ask me to identify the insect she found - and it was a tiny red and black wasp, which was crawling on her hand. Kudos to her for not freaking out when I said "Oh, it's a wasp!" She was completely unfazed by it. We talked about how it was likely an important pollinator and possibly even parasitic on other critters, like caterpillars. A classmate joined our conversation, and both were very serious in their investigation of this insect...and reassured when I told them that the odds of it harming them were pretty slim.

Checking out the seeds on the Canada Wild Onion.

Nuts are still all over the place (hickories, walnuts and acorns), although there are significantly fewer than there were a month ago. We found the mother load of acorns by the picnic tables on the island in the middle of the parking lot. Could it be that because cars drive around it that the squirrels hadn't gathered these nuts yet? Whatever the reason, it was a boon for us, as each child learned to make a top and a whistle from their finds.

Then we were off down the trail...but only for a short distance, for they saw a "clearing" in the woods that was so tempting that they eagerly asked if they could go check it out. What the heck - why not! So off the trail we went, on a genuine "explore" into the unknown.

We found ourselves in a little hollow under a fallen tree that just made the best exploration spot for second graders. They looked at the logs, pulled off bark, jumped over the dry "stream" bed, pet some moss (after admiring the way the sun shone through the russet sporophytes).

After bushwhacking back to the trail, they saw the deer exclosure (cage), and said "can we go there?!?!" Absolutely - I'd never explored it myself, so it was new to me, too. We discovered that the cage also had fencing over the top...once upon a time. That fencing has now sagged and collapsed into the cage. The kids found a "door" on the back side, so of course they had to go inside. We talked about the purpose of the exclosure, but second graders aren't really concerned about browsing pressure. They were intrigued, however, when I mentioned the Severson Dells legend of Humphrey the Dragon, who supposedly uses the cage as a home.

We completed our walk around the trail, stopping at the pond to look for turtles (none), frogs (nope) and dragonflies (zero). And then we went to The Grove, where running and climbing were the order of the day.

I know I certainly had a great time exploring the unknown with these students, and I think they did, too. I worked with a volunteer once who said that everyone needs to "step off the sidewalk" from time to time, which is exactly what we did this day. The next time you go out, take a chance and step off the sidewalk in your explorations - even if only for a few steps (and watch where you walk - be aware of your surroundings). You might be amazed at what you find.

Severson Dells Nature Center

Our Mission: To link people to nature through education and research, in the northern Illinois and southern Wisconsin area. We promote awareness of the natural world, fostering respect, enjoyment, and preservation now and in the future.